Multi-element electrothermal AAS determination of 11 marker elements in fine ambient aerosol slurry samples collected with SEAS-II

Abstract

Multi-element simultaneous electrothermal atomic absorption spectrometry (ETAAS) methods were developed for determining 11 elements, in three analytical groups (group-1, predominately crustal elements, Al, Cu, Fe, Mn, and Cr; group-2, tracers of coal and oil combustion as well as other anthropogenic sources, Se, As, Pb, and Ni; and group-3, tracers of municipal incinerator aerosol–Zn and Cd), in aqueous slurry of ambient fine airborne particles, collected, at 30 min intervals with the University of Maryland–Semicontinuous Elements in Aerosol Sampler-II (SEAS-II). Combined effects of acid (0.2% v/v nitric acid) and ultrasonic treatment (15 min) improved metals recovery and slurry stability. Linear calibration ranges were improved by using a 50 mL min −1 carrier gas flow (mini-flow) during the atomization stage. However, analytical sensitivity for group-1 and 3 elements was compromised. Palladium (4 μg) and hydrogen (5% in Argon) were found to be effective modifiers for group-1 and 2 elements. A fast furnace temperature program was developed for group-3. Detection limits for the eleven marker elements by the SEAS-II-ETAA approach were compared with traditional filter X-ray fluorescence, laser ablation-ICPMS, and instrumental neutron activation analysis (INAA) techniques used in air quality studies. The efficacy of the analytical method was evaluated by analyzing interim urban PM2.5 reference material, collected in Baltimore, by the National Institute of Standards and Technology (NIST) Gaithersburg, MD. Results obtained by the ETAAS methods agreed well with the results obtained by NIST using INAA.